Numerous environmental risks need to be considered as early as possible in the consideration of alternative hydropower development options.  In the absence of a sound environmental assessment, issues that could have been avoided or minimised can become problematic in the long term – issues related to key ecosystem components such as water quality, biodiversity, passage of aquatic species, pest species, erosion and sedimentation, alongside and almost invariably interlinked with many social issues. 

In some parts of the world, environmental assessments are requirement of the development process; however this is not the case in all parts of the world, and regulatory frameworks vary considerably across the nations. Quality of environmental assessments is also a key issue – if not based on sound science and a strong research and monitoring program, they will not be credible nor achieve their intentions.  

Monitoring is essential to determine the extent of scheme alteration of the natural environment, and the causative and compounding factors of any problem areas. An inadequate monitoring program does not allow assessment of effectiveness of mitigation measures, which greatly limits the ability of the hydropower industry to learn from collective experience. Monitoring may be done for compliance reasons, but unless the data are regularly evaluated by appropriately qualified personnel it may not be adequately informing management.